P566: IMPACT OF FRONTLINE INDUCTION APPROACH ON POST-STEM CELL TRANSPLANT (SCT) OUTCOMES IN OLDER ADULTS WITH NEWLY DIAGNOSED ACUTE MYELOID LEUKEMIA (AML)
Authors: F. Ong, F. Ravandi, U. Popat, T. M. Kadia, N. Daver, C. DiNardo, M. Konopleva, G. Borthakur, E. J. Shpall, B. Oran, G. Al-Atrash, R. Mehta, E. J. Jabbour, M. Yilmaz, G. C. Issa, G. Garcia-Manero, A. Maiti, H. A. Abbas, R. E. Champlin, N. J. Short
Journal: HemaSphere (2022)

Background: A hypomethylating agent plus venetoclax (VEN) is standard of care for older, unfit patients (pts) with newly diagnosed AML. However, the optimal induction regimen for older pts with AML who are adequately fit for SCT is not well-established. Aims: We investigated the post-SCT outcomes of older adult pts with newly diagnosed AML based on the intensity of the induction regimen received. Methods: This is a retrospective analysis of pts ≥60 years (yr) of age with newly diagnosed AML who received allogeneic SCT after achieving first remission (CR, CRi or MLFS) between 9/2012 and 7/2021 at our cancer center. Out of 127 pts, 44 pts received intensive chemotherapy (IC) without VEN as induction therapy, 36 pts received low-intensity therapy (LIT) without VEN, and 47 pts received LIT with VEN. Overall survival (OS), relapse-free survival (RFS), cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) after SCT were compared among the groups. Results: The baseline characteristics of the groups are shown in Table 1. Pts in the IC cohort was significantly younger (median age of 63 yrs) than pts who received LIT with or without VEN (median age of 68 yrs, p<0.01). Pts in the IC group were more likely to have ECOG PS of 0 (34%) as compared to those who received LIT (14%, p=0.07). Most pts had adverse ELN cytomolecular risk on presentation (43% in IC, 50% in LIT without VEN, and 55% in LIT with VEN). The median numbers of cycles prior to SCT were 3 in all groups. Pts in LIT without VEN group were more likely to receive matched unrelated donor (75%) than those in the LIT with VEN (49%) and IC groups (50%) and were less likely to receive a haploidentical SCT (3% vs. 17% and 14%, respectively). Pts in LIT with VEN group were more likely to receive reduced-intensity conditioning (92%) prior to SCT, compared with 53% and 58% in the IC and LIT without VEN groups, respectively (p<0.01). HLA matching was well-balanced in 3 groups. The majority of pts were in CR/CRi prior to SCT (100% in the IC group, 95% in the LIT without VEN group, and 92% in the LIT with VEN group), while the rest of pts achieved MLFS. MRD negativity prior to SCT was achieved in more pts treated with IC (77%) or LIT with VEN (66%), compared with LIT without VEN (49%). For the entire cohort, the median follow-up was 37 months (mos) post-SCT. Post-SCT outcomes are shown in Figure 1. The 2-yr OS was highest in the LIT with VEN group (73%) when compared with the IC or LIT without VEN groups (58% and 44%, respectively); OS was statistically superior with LIT with VEN compared with LIT without Ven (p=0.02) and there was a trend towards superior OS compared with IC (p=0.17). 2-yr RFS was also superior in the LIT with VEN group (62%) as compared with the IC or LIT without VEN groups (54% and 42%, respectively). 2-yr CIR was highest in LIT without VEN group (36%), and was similar in the LIT with VEN (19%) and IC groups (18%). 2-yr NRM was highest in IC group (27%) as compared with the LIT with VEN (11%) and LIT without VEN groups (22%) (p=0.02 for IC vs. LIT with VEN). Image:Summary/Conclusion: LIT with VEN resulted in comparable—and possibly superior—outcomes compared with IC in SCT eligible patients ≥60 yrs with newly diagnosed AML. Despite the older age and worse PS of the LIT with VEN group, their post-SCT NRM was lower than those who received IC, which translated to numerically superior OS. These results support LIT with VEN as an effective and tolerable induction strategy in older SCT-eligible pts with newly diagnosed AML.